The disclosure relates to a process cartridge and an image forming apparatus equipped with the process cartridge.
Conventionally, a process cartridge is loaded into an image forming apparatus, such as a laser printer. The process cartridge includes a photosensitive drum on which an electrostatic latent image is formed and a developing cartridge that develops the electrostatic latent image formed on the photosensitive drum into a toner image.
The developing cartridge is mounted to a drum cartridge supporting the photosensitive drum. The developing cartridge includes a developing roller that supplies toner onto a surface of the photosensitive drum. As the developing roller rotates in a state where the developing cartridge is mounted to the drum cartridge and the developing roller faces the photosensitive drum, toner is supplied to the surface of the photosensitive drum from the developing roller. An electrostatic latent image is thus developed into a toner image. The developed toner image is then transferred onto a sheet, which is fed between the photosensitive drum and the transfer roller, by the transfer roller disposed opposite the photosensitive drum.
For example, U.S. Pat. No. 6,751,428 discloses such a process cartridge including a locking device for maintaining a state where the developing cartridge is attached to the drum cartridge. In the process cartridge, the drum cartridge includes a shaft that extends along an upstream end face in a developing cartridge attaching direction, and a locking lever that is rotatably supported by the shaft. The developing cartridge includes a locking protrusion that protrudes therefrom toward the upstream side in the developing cartridge mounting direction. The locking lever is rotated about the shaft to engage the locking protrusion in order to prevent the developing cartridge from becoming detached from the drum cartridge. By doing so, the attachment of the developing cartridge to the drum cartridge is maintained.